JPS6211880A - Developing device for electrophotography - Google Patents

Abstract

PURPOSE:To prevent surely mixed development by toners of two colors by constituting the titled device so that when one developing sleeve has been oscillated so as to approach a photosensitive body, on the contrary, the other developing sleeve is oscillated in the direction being separated from the photosensitive body. CONSTITUTION:A developing roller consisting of developing sleeves 13, 23 and magnets 14, 24 is provided on cases 11, 21, respectively. As for each case 11, 21, a supporting shaft 31 is supported by a U-shaped bearing 32, and the developing sleeves 13, 23 are attached so as to be oscillatable on the photodetecting surface of a photosensitive body 1. Also, both end sides of an interlocking body 34 are linked to both the cases 11, 21, respectively, so that when one developing sleeve has been oscillated so as to approach the photosensitive body 1, the other developing sleeve is oscillated in the direction being separated from the photosensitive body 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic developing device in an image recording device such as an electrostatic copying machine or a facsimile machine. The present invention relates to a developing device for electrophotography in which a developing case is provided, and a developing roller comprising a developing sleeve and a magnet is provided in each of the developing cases.

[Conventional technology]

The above-mentioned developing device performs monochrome development in which one of the different color developers stored in the development case is selected for development, or
It was developed to be compatible with superimposed development in which the above two color developers are developed sequentially.
There is one disclosed in Japanese Patent No. 4469.

This developing device has a pair of cases fixed separately around the photoconductor surface of a drum-shaped photoconductor to house developers of different colors. The sleeves formed by the above are rotatably attached to each other, and a magnet roller is rotatably provided within each of the sleeves.

To develop electrophotography using this developing device, a magnetic roller in a sleeve of a case containing developer of the color used for development is rotated to a position where its main pole faces the photoreceptor, and the sleeve and photoreceptor are separated. On the other hand, a magnetic roller in the sleeve of a color not involved in development is rotated so that its main pole is deviated from the photoconductor to form spikes of developer on the opposing sleeve surfaces. By placing the stand away from the photoreceptor, the influence of toner of colors that are not involved in development is eliminated.

[Problem that the invention seeks to solve]

The conventional developing device described above rotates one of the magnets provided in each sleeve and changes the position of its main pole with respect to the photoreceptor, thereby performing development with a developer of a desired color. Changing the phase of the magnetic roller over 180 degrees using a solenoid would be structurally extremely complex, but we had to rotate the magnetic roller only a little to align the valleys of the developer spikes with the photosensitive surface. Although the structure of the driving rotation becomes simpler when the developing sleeve is placed facing the photoreceptor, the gap between the developing sleeve and the photoreceptor surface is extremely small, so that the toner of the color that is not involved in the development forms the latent image on the photoreceptor. It may be attracted to the surface and a portion of a different color may be developed.

In addition, since the magnet roller is driven electrically, the spikes of each developing sleeve may be formed corresponding to the photosensitive surface due to electrical malfunction or the like.
There is also the problem that two color developers may come into contact with the photoreceptor at the same time.

The present invention has been made to solve the above-mentioned problems, and aims to eliminate the possibility of mixing of different color developers and to provide a developing device for electrophotography that does not malfunction.

[Means for solving problems]

In order to achieve the above object, the electrophotographic developing device according to the present invention includes: the developing case is provided to be swingable around an axis parallel to the rotation axis of the photoreceptor, and the developing sleeve is attached to the photoreceptor of the photoreceptor. The structure is configured such that it can be freely switched between a state in which it approaches a surface and a state in which it moves away from the surface, and each end of a rocking interlocking body whose intermediate portion is pivotally supported is linked to the developing sleeve separately, so that the developing sleeve can be selected. The present invention is characterized in that it is configured so as to switch to the approach state and is provided with a driving means for swinging the developing case or the interlocking body.

[Effect]

The developing device of the present invention is configured as described above, that is, by the rocking of one case or the interlocking body, the other case is rocked in a direction opposite to the rocking direction of the case, and the developing device is When the sleeve in one case approaches the photoreceptor, the sleeve in the other case moves away from the photoreceptor, so only the developer magnetically attracted to one sleeve is brought closer to the photoreceptor. can be brought into contact with the photoconductor, and the developing sleeve 1, which is magnetically attracted to the other sleeve, can be prevented from coming into contact with the photoconductor.

Furthermore, since the distance between the sleeve that is not involved in development and the photoconductor surface of the photoconductor can be widened, it is possible to prevent the toner of the developer that is not involved in development from being attracted to the photoconductor. Since the pair of cases is swung in conjunction with each other by the oscillation of the interlocking body, when one sleeve approaches the photoconductor, the other sleeve always moves far away from the photoconductor, and both sleeves approach the photoconductor. Never.

〔Example〕

An electrostatic copying machine showing an embodiment of the developing device of the present invention in the drawings will be described.

FIG. 1 is a sectional view showing the main parts of an electrostatic copying machine.

In the figure, reference numeral 1 denotes a drum-shaped photoreceptor, which is attached to a fixed part 2 such as the body of an electronic copying machine.
1.52, the copy paper transport section 6, the transfer device 7, the copy paper separation device 8, the copy paper transport device 9, and the cleaning device 10 are arranged in the rotation direction K of the photoreceptor 1 in the above-mentioned order. P is an exposed portion of the photoreceptor 1.

The developing device 51 is configured as follows.

That is, a toner replenishing hopper 1 is installed in the upper part of a developing case 11 that accommodates a two-component developer containing a mixture of l-toner and carrier.
5 and the photoreceptor 1 of the developing case 11.
The developing roller R
1 is provided.

The developing roller R1 includes a developing sleeve 13 made of a non-magnetic material that is rotatably provided with its axis directed in the same direction as the axis of the photoreceptor 1, and a developing sleeve 13 that is provided within the developing sleeve 13 with an interval in the circumferential direction. It consists of a magnet 14.

Reference numeral 16 denotes a toner supply roller provided at the lower part of the hopper section 15, which causes the toner in the hopper section 15 to fall appropriately to the lower part of the case 11. 17 is a roller for stirring the developer provided at the lower part of the case 11, and 18 is a doctor blade made of a non-magnetic material.

The structure of the developing device 52 is similar to that of the above-described developing device 51, and the developing case 21 with the toner hopper section 25 connected thereto is formed in an L-shape, and the protrusion at the bottom thereof is disposed below the case 11. Further, inside the opening 22, a developing roller R2 consisting of a sleeve 23 made of a non-magnetic material and a magnet 24 is provided.

26 is a toner supply roller provided in the hopper section 25; 27;
28 is a stirring roller, and 28 is a doctor blade.

As shown in FIG. 2, the developing devices 51 and 52 connect support shafts 31 protruding from the top of both ends of the photoreceptor 1 in the axial direction of each case 11.21 to a fixed portion 2 of the machine body or the like. Supported by a fixed bearing 32 having a U-shaped cross section, the developing sleeve 13.23 is attached so as to be able to swing toward and away from the photosensitive surface of the photosensitive member 1.

Reference numerals 33 and 33 denote locking pins protruding from the surface of the case 11 and 21 on which the support shaft 31 is provided, and 34 an interlocking body constituted by a band-shaped plate, the intermediate part of which in the longitudinal direction is connected to the fixed The locking pin 3 is swingably attached to the section 2 with a mounting shaft 35, and is fitted into locking recesses 36°36 provided at both ends of the locking pin 3.
3.33 are linked together so that the cases 11.21 swing simultaneously and in opposite directions via the linking body 34.

The locking recess 36 for the locking pin 33 on the case 11 side of the interlocking body 34 is open at one end in the longitudinal direction of the interlocking body 34, and the other locking recess 36 is opened at the upper surface of the interlocking body 34 in the longitudinal direction. Therefore, in either case 11 or 21, the support shaft 31 can be engaged with the bearing 32, and the locking pin 33 can be engaged with the locking recess 36 from above. . On the contrary, it is also easy to pull out the case 11.21 upward, and the developing device 5
1.52 maintenance can be conveniently carried out in a large area outside the aircraft.

Is 37 a developing bag? i! A support bar 38 is provided on the fixed part 2 and is a driving means for swinging the developing device 52, which is rotatable around an axis parallel to the axis of the photoreceptor 1. A cam 39 that is in contact with the surface of the case 21 on the side opposite to the photoreceptor 1 is fixed to the support bar 38, and a rod axis is inserted into the elongated hole at the other end of the link 40 so that the case 21 swings. Slide rods 43 of solenoids 41 and 42 arranged opposite to each other in the direction
．． 44 are connected in a locking manner, and the solenoids 43 and 44 are
By selective excitation, one of the developing sleeves 13 is brought close to the photosensitive surface of the photoreceptor 1 (see FIG. 2), and the other developing sleeve 23 is brought close to the photosensitive surface (see FIG. 3). It is possible to switch.

The state in which the one developing sleeve 13 approaches is due to the gravitational bias of the developing device 52, which is large in weight, and the state in which the other developing sleeve 23 approaches is due to excitation that opposes the gravitational bias. It is by force.

Therefore, depending on the appropriate setting of the gravity bias, the solenoid 42 that switches the one developing sleeve 13 to the approaching state
It is also possible to omit it.

Next, 45a and 45b are first and second gears having the same number of teeth that mesh with each other, and an input gear 45C meshes with the first gear 45a.

Further, when the one developing sleeve 13 is close to the photosensitive surface, the gear 46a connected to the sleeve 13 is moved to the second gear 4.
5b and is connected to the other developing sleeve 23 with the other developing sleeve 23 approaching the photosensitive surface.
6b meshes with the first gear 45a. Then, as the input gear 45C rotates in the direction A opposite to the rotation direction of the photoreceptor 1, the one developing sleeve 13 is rotated in the opposite direction R with respect to the photoreceptor I at the portion facing the photoreceptor 1. The other developing sleeve 23 rotates in the forward direction F with respect to the photoreceptor 1 at the portion facing the photoreceptor 1 .

In the above configuration, for example, one developing device 51 stores a red developer made of toner and carrier, and the other developing device 52 stores a black developer.

When developing with black developer, the solenoid 41 is activated and the cam 39 pushes the developing device 52, as shown in FIG. Then, the sleeve 23 of the developing device 52 approaches the photoreceptor, and the sleeve 23 rotates in the direction of arrow F, developing the latent image on the photoreceptor 1 with the black toner magnetically attracted to the surface of the sleeve 23. At the same time, due to the swinging of the developing device 52, the interlocking body 34 swings about the mounting shaft 35, and the developing device 51 moves toward the photoreceptor 1.
It will swing in the direction away from.

As a result, the sleeve 13 of the developing bag W51 is attached to the photoreceptor 1.
Since the developing sleeve 13 is far away from the photosensitive surface of the developing sleeve 13, it is possible to avoid two-color mixed development due to the red toner of the developing sleeve 13 being attracted to the photosensitive member 1.

When developing with red developer, as shown in Figure 3,
This releases the pressure on the developing device 52 by the cam 39, and as the developing device 52 swings away from the photoreceptor 1 due to gravity bias, the developing device 5
1 swings toward the photoreceptor 1 side, the developing sleeve 13 of the developing device 51 rotates in the direction of arrow R, and development is performed using only red toner.

In the above embodiment, the driving means 37 pushes the developing device 52, but it is also possible to push the developing device 51, or instead of the developing devices 51 and 52, the interlocking body 34 can be swung by the driving means 37. It can also be carried out.

Alternatively, instead of the cam 39, one end of a plate or a rod is attached to the support bar 38, and the other end is pivotally attached to the developing device 51, 52 or the interlocking body 34, so that both forward and backward movement of the developing device 52 can be achieved. It is also possible to forcibly perform this by the driving means 37, and as the driving means 37, an arbitrary configuration can be adopted.

Therefore, the position of the support shaft 31 in the developing device 51, 52 is arbitrary, and it is sufficient if the developing device 51, 52 is made swingable.

Further, in addition to the above-described structure of swinging the developing device, a structure of rotating the magnets 14 and 24 may be adopted.

Further, it is also possible to apply the present invention to a developing device using a monocomponent developer containing only magnetic toner.

〔Effect of the invention〕

As described above, the present invention includes two cases each provided with a developing sleeve and a developing roller consisting of a magnet, which are swingably mounted, and both ends of the interlocking body, the intermediate portion of which is pivotally supported, are connected to the two cases. If one of the developing sleeves is swung toward the photoconductor from the two linked cases, the other case swings away from the photoconductor, so that the sleeve and photoconductor are It is possible to have a large interval between the two colors, and mixed development using two color toners can be reliably avoided.

Since the two cases are moved together by the interlocking body, the operation of swinging one case toward the photoreceptor and swinging the other case away from the photoreceptor is always repeated reliably. It is possible.

[Brief explanation of drawings]

FIG. 1 is a front view of essential parts of an electrostatic copying machine showing one embodiment of the present invention, and FIGS. 2M and 3 are explanatory views showing a state in which a developing device is alternatively approached. 1... Photoreceptor, 11.21... Case, 13.23
...Developing sleeve, 14.24...Magnet, 3
4... Interlocking body, 37... Drive means.

Claims (1)

[Claims] A developing device for electrophotography, in which two developing cases are provided around a photoreceptor, and a developing roller consisting of a developing sleeve and a magnet is provided in each of the developing cases, and the developing case is connected to the rotation of the photoreceptor. The developing sleeve is provided so as to be swingable around an axis parallel to the axis, and can be freely switched between a state in which the developing sleeve approaches the photosensitive surface of the photoreceptor and a state in which it moves away from the photosensitive surface of the photoreceptor. a drive for oscillating the developing case or the interlocking body, the end portions of the movable interlocking body being configured to individually interlock with the developing sleeve to selectively switch the developing sleeve to the approaching state; and a drive for swinging the developing case or the interlocking body. A developing device for electrophotography, characterized in that it is provided with means.